Skin mast cells play an important role in cutaneous inflammation, especially immunoglobulin-E (IgE)-mediated early type, complement-mediated, and T cell-mediated delayed type hypersensitivity reactions. They can synthesize and release various preformed and newly formed mediators that are important in the pathobiology of certain diseases such as urticaria, mastocytosis, atopic dermatitis, contact dermatitis, bullous pemphigoid, scleroderma, psoriasis, and parasitic skin infections. They also have important functions in parasite infestations, angiogenesis, and tissue remodeling besides allergy and inflammation. Their origin, morphology, distribution, heterogeneity, function, activation, and mediators are included in the subject. Interactions of mast cells with their microenvironment and the other cells, and their role in some pathobiological situations are briefly outlined. This article will reinforce the reader's knowledge of the recent concepts on human cutaneous mast cells.